GitLab

 1. Puts the "Enter required custom passphrase" UI at the top of the Sync page.

 2. Auto-focuses the passphrase field when the passphrase is required.

BUG=694115
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2755793002
Cr-Commit-Position: refs/heads/master@{#457505}